Halomethyl, methyl maleic anhydride and synthesis of bromomethyl, methyl maleic anhydride

ABSTRACT

Quaternary ammonium compounds containing anhydride groups are prepared by halogenating dimethylmaleic anhydride and reacting the halogenated product with a tertiary amine. The products are useful as surfactants, biocides and as cosurfactants in enhanced oil recovery.

FIELD OF THE INVENTION

This invention relates to quaternary ammonium compounds containinganhydride groups that are derived from dimethylmaleic anhydride. Moreparticularly, this invention relates to quaternary ammonium compoundsprepared by halogenating dimethylmaleic anhydride with a halogen, anallylic halogenating agent, or a free radical halogenating agent andreacting the methyl halomethylmaleic anhydride with tertiary amineswherein the said quaternary ammonium compounds are of the structuralformula: ##STR1## wherein R is selected from the group consisting ofalkyl groups of 1 to 20 carbon atoms, aryl groups of 6 to 18 carbonatoms, aralkyl groups with 7 to 19 carbon atoms, heterocyclic groupswith 4 to 20 carbon atoms, and cycloalkyl groups with 5 to 12 carbonatoms.

For convenience these compounds are referred to as quaternary ammoniumcompounds containing anhydride groups. These compounds possess biocidalproperties. The invented compounds of molecular weights within the rangeof from about 400 to about 1200 act as cosurfactants useful in enhancedoil field recovery. These compounds are also useful as surfactants andbiocides, and can be used as hydraulic fluids when of sufficiently lowmolecular weight, and as chemical intermediates.

Cosurfactants function as coupling agents for surfactants and reservoirbrines for the purpose of enhancing crude oil production. Surfactant andcosurfactant mixtures are dissolved in brines in low concentrations toform micellar fluids or solutions. These micellar solutions can bedescribed as microemulsions containing surfactants which act to reducethe interfacial tension between water and oil. A second component, acosurfactant, usually an alcohol, is used to improve the quality of themicellar solution. An efficient cosurfactant increases the micelles'capacity to solubilize more oil or water and still form stabilizedsolutions.

Compounds used as cosurfactants in the prior art have been alcohols suchas isopropyl alcohol, amyl and hexyl alcohols and their ethoxylatedderivatives. These cosurfactants have limited capabilities because ofthe variety of reservoir conditions encountered in enhanced oil recoveryprograms. For example, special systems must be designed for reservoirswhich are essentially fresh water, that is, those which contain 6000 ppmor less monovalent ions, and those which are essentially hard water,those which contain 50,000 ppm monovalent ions plus 500 ppm or more ofdivalent ions. Cosurfactants should perform so as to achieve a stablefluid when the water-cosurfactant mixture is in contact or mixed withcrude oil. Molecular weight of the cosurfactant should be sufficientlylow to permit passage through semipermeable rock formations and achievemobility control.

This invention accordingly relates to a new and unique family of lowmolecular weight compounds which are suitable for use as cosurfactantsfor enhanced crude oil recovery. These compounds in use lower theinterfacial tension between water and oil, are low molecular weight offrom about 400 to about 1200, and are required in only lowconcentrations to formulate micellar fluids.

SUMMARY OF THE INVENTION

This invention relates to quaternary ammonium compounds containinganhydride groups that are derived from dimethylmaleic anhydride, andthat are useful as cosurfactants in enhanced oil recovery, surfactantsand biocides, and as hydraulic fluids when of sufficiently low molecularweight.

DETAILS OF THE INVENTION

Quaternary ammonium compounds containing anhydride groups are preparedby halogenating dimethylmaleic anhydride with an allylic halogenatingagent and reacting the methyl halomethylmaleic anhydride with tertiaryamines according to the following reaction: ##STR2##

R₁ can be halogen, such as chlorine or bromine, succinimido andtrichloromethyl. X is halogen and can be iodine, bromine, chlorine andfluorine. Chlorine and bromine are preferred because of availability andcost.

The tertiary amine, (R)₃ N, can be a trialkyl amine wherein the alkylgroup can be of 1 to 20 carbon atoms. Examples of such trialkyl aminesare trimethylamine, triethylamine, tributylamine, lauryldimethylamine,stearyldimethylamine and tri-n-octylamine. The tertiary amines can beheterocyclic amines selected from the group consisting of pyridine,quinoline, isoquinoline, phenanthridine and N-methylpyrrolidine.Examples of aralkyl amines are benzyldimethylamine, benzyldibutylamine,and naphthylmethyl dimethylamine.

Preferably the tertiary amine comprises an amine comprisingtrioctylamine, triethylamine, trihexylamine, stearyldimethylamine andpyridine. These are preferred because they are cheap, reactive and coverthe range of derivatives in various inorganic and organic solvents. Oneor more hydrogens of the aliphatic, alicyclic, heterocyclic and aromaticmoieties of the above-described amine compounds can be replaced withnonreactive radical groups such as cyano and alkoxy radicals.

The molar ratios of the reactants to prepare the quaternary ammoniumcompounds containing anhydride groups, i.e., the allylic halogenatingagent, and the anhydride that can be used, can vary. The agent-anhydrideratio is between 1 to 3 moles of agent per mole of anhydride.Substantially equimolar amounts of agent and anhydride are preferred.Use of a solvent such as heptane, hexane, benzene, acetone,dichloromethane, dioxane or carbon tetrachloride at concentrations of 1to 85 weight percent is convenient.

Dichloromethane is the preferred solvent.

The reaction can be run in any type of open or sealed vessel, suitablyagitated, equipped with means of heating the contents and with refluxcapabilities.

The present invention also comprises a method of injecting a micellerslug into a subterranean formation comprising the steps of (1)contacting said subterranean formation with an aqueous fluid compositioncomprising water, a surfactant, a hydrocarbon, and an electrolyte and alow molecular weight quaternary ammonium compound containing anhydridegroups within the range of from about 400 to about 1200; (2) applyingsufficient pressure to said composition to cause said micellar slug tomove through said formation; (3) maintaining sufficient pressure whileinjecting said composition into said formation. The said low molecularweight quaternary ammonium compounds can be selected from the groupconsisting of compounds prepared from trioctylamine, trihexylamine andstearyldimethylamine.

In order to facilitate a clear understanding of the invention, theprocess of preparing quaternary ammonium compounds containing anhydridegroups and the use thereof, the following specific embodiments aredescribed in detail. It should be understood, however, that the detailedexpositions of the instant invention, while indicating preferredembodiments, are given by way of illustration only since various changesand modifications within the spirit and scope of the invention willbecome apparent to those skilled in the art from this detaileddescription.

PRELIMINARY EXAMPLE

Screening tests for suitable cosurfactants to be used as additives forenhanced oil recovery have been developed which indicate a relationshipexists between interfacial tension of the cosurfactant and petroleumremoval from core samples using a micellar solution.Surfactant-stabilized dispersions of water in hydrocarbon are micellarsolutions. In addition to the required surfactant, water andhydrocarbon, micellar solutions can contain cosurfactants andelectrolytes to improve stability. Alcohols such as isopropanol and amylalcohols typically have served as cosurfactants. Sodium chloride andsodium sulfate are examples of electrolytes that are used.

Important aspects of a micellar solution include an ability tosolubilize water, compatibility with hydrocarbon and crude oil, anincreasing viscosity with increased water concentration and inversion toan oil-in-water solution. In a micelle, surfactant and cosurfactantsurround dispersed water which exists in the hydrocarbon phase asspherical droplets. With additional water, the water droplets increasein size. When water is in dispersed phase, the micellar solutionsexhibit hydrocarbon-like properties of the external phase. As more andmore water is solubilized in a micellar system, spheres enlarge untilinversion takes place to form an oil-in-water emulsion. Cosurfactants ina miscellar solution stabilize the solution to reduce incidence ofinversion and phase separation.

The following bench test has been devised as a preliminary vialscreening test to eliminate need for expensive core tests ofcosurfactants. The test has been found to have reliability in predictingsuitable properties of cosurfactants when used in micellar solutions.The principal important aspect has been found to be the interfacialtension of the cosurfactant in an oil-water mixture. The formulation isrequired to yield stable fluids in brine and to show low interfacialtension (IFT) as well as very good miscibility with crude petroleum.

Micellar fluids formulated from concentrates containing 40:1 to 5:1surfactant-cosurfactant ratios have been tested over a wide range ofsalinities (sodium chloride in water) and hard waters, being examinedfor phase stability, fluid clarity, interphase behavior and miscibilityof aqueous fluids with crude petroleum.

The vial screening bench test is an empirical test which comprisesmixing the micellar fluid and crude petroleum by swirling the fluidstogether in a test tube while observing the interface. A light source isused to observe the fluid-oil behavior. The interfacial mixing (andhence interfacial tension) is judged upon a scale of very low,moderately low, low, medium and high by a comparison with standardspreviously developed.

For example, brine solutions of a hardness range from under 6,000 ppm ofmonovalent ions (sodium chloride) to about 50,000 ppm of monovalent ions(sodium chloride) are mixed with a 40:1 ratio of surfactant-cosurfactantmixture with Second Wall Creek crude. The surfactant is a petroleumsulfonate. Surfactant-cosurfactant-brine mixtures are prepared atambient temperature and pressure.

Stability of the brine solution with surfactant-cosurfactant mixture istested by pouring the mixture into a 50 ml graduated cylinder andallowing the solution to stand for one hour undisturbed. Fluids whichremain single phase and free of sediment are further tested. 20 ml ofsolutions are poured into a vial. 4 ml of crude petroleum are added tothe vial. The vial is turned gently, observing mixing behavior of crudeand micellar fluid. The vial is then shaken vigorously for one minute,after which the vial is allowed to stand undisturbed for one hour. Afterthis period, the fluid is evaluated for oil drop-out, number of liquidphases, thickness of emulsion and miscibility. Results are correlatedwith interfacial tension of solution and crude by visual observation andspinning drop method of J. L. Caylas, et al., "Low Interfacial Tension,"American Chemical Society Series No. 8 Adsorption At Interfaces, 1975.Formation of round oil droplets which separate quickly, and failure toform an emulsion, indicate a high, ineffective interfacial tensioncharacteristic which can render the cosurfactant unsuitable as anadditive for enhanced oil recovery applications.

EXAMPLE I

A mixture of 12.6 g (0.1 mole) of dimethylmaleic anhydride, 17.8 g (0.1mole) of N-bromosuccinimide, 0.2 g of benzoyl peroxide, and 150 ml ofcarbon tetrachloride was stirred and refluxed for 26 hours. At 10 hours,we added another 0.2 g of benzoyl peroxide. The mixture was cooled to25° C. and filtered, giving 10 g of succinimide (theory, 9.9 g). Thefiltrate was diluted with 50 ml of n-hexane, the lower layer separatedand evaporated, giving 18.02 g (88 mole% yield) of orange, viscous oilas product. It was distilled in vacuo. All but a few drops distilled asa thick yellow oil at 103°-110° C. (0.35 mm).

Anal. Calcd. for C₆ H₅ BrO₃ :C,35.1; H,2.4; Br,39.0. Found: C,34.6;H,2.5; Br,38.2.

EXAMPLE II

A solution of 12.6 g (0.1 mole) of dimethylmaleic anhydride in 38.45 ml(0.3 mole) of bromotrichloromethane was irradiated with a 275 watt G. E.sunlamp at 70°-80° C. for 19 hours. Distillation gave 5.5 ml ofchloroform at 62°-80° C., 24 ml of bromotrichloromethane at 80°-90° C.(200 mm), and 15.12 g of methyl bromomethylmaleic anhydride at 102°-106°C. (0.2 mm).

Anal. Calcd. as in Example I. Found: C, 35.6; H, 2.6; Br, 38.1.

The products of both Examples I and II showed peaks for CH₂ Br at 4.25ppm in the H spectrum and at 16.0 ppm in the ¹³ C spectrum.

EXAMPLE III

To a solution of 2.18 g (10 mmoles) of the product of Example I in 5 mlof dichloromethane was added a solution of 4.37 ml (10 mmoles) oftri-n-octylamine in 5 ml of dichloromethane. The solution became hot andturned deep purple. After two days at 25° C. the mixture was dilutedwith 10 ml of tert-butanol and evaporated at 80° C. to constant weight.The product, ##STR3## was an extremely viscous, dark oil that weighed5.57 g (98 mole% yield).

Anal. Calcd. for C₃₀ H₅₆ NBrO₃ :C, 64.5; H, 10.0; N, 2.5; Br, 14.3.Found: C, 64.8; H, 10.4; N, 2.8; Br, 14.0.

EXAMPLE IV

To a solution of 2.18 g (10 mmoles) of methyl bromomethylmaleicanhydride (Example I) in 5 ml of dichloromethane was added a solution of2.7 g (10 mmoles) of tri-n-hexylamine in 5 ml of dichloromethane.Treatment of the dark purple solution and workup as in Example II gave4.4 g (90 mole% yield) of extremely viscous dark oil.

Anal. Calcd. for C₂₄ H₄₄ NBrO₃, ##STR4## C, 60.8; H, 9.3; N, 3.0; Br,16.9. Found: C, 61.2; H, 9.2; N, 3.4; Br, 16.2.

EXAMPLE V

A mixture of 2.18 g (10 mmoles) of methyl bromomethylmaleic anhydrideand 0.791 g (10 mmoles) of pyridine, each dissolved in 5 ml ofdichloromethane, was treated as in Example III. The product was a dark,hygroscopic solid, 2.9 g (100% yield).

Anal. Calcd. for C₁₁ H₁₀ NBrO₃, ##STR5## C, 46.5; H, 3.5; N, 4.9; Br,28.2. Found: C, 46.1; H, 3.9; N, 5.4; Br, 27.8.

EXAMPLE VI

The effectiveness of these novel compounds as surfactants in loweringinterfacial tension between solvent-extracted 5W oil and water wasmeasured using a Cenco-Du Nouy Interfacial Tensiometer No. 70545 with a6 cm platinum-iridium ring at 25° C., with double-distilled water, withthese results at 1 wt% concentrations.

    ______________________________________                  Interfacial    Product       Tension, dynes/cm    ______________________________________    Control       41.73    Example III   11.23    Example IV    13.66    Example V     19.80    ______________________________________

EXAMPLE VII

Control of microorganisms in inhibiting or preventing growth of fungi inenhanced oil recovery operations is a desirable characteristic of usefuladditives.

The product of this invention was tested as a biocide and inhibitor forthe growth of microorganisms by this test: 25 g of agar preparation wereplaced in standard petri dishes. The agar preparation consisted of 23.5g of Bacto Plate Count Agar, Difco Laboratories, Detroit, Mich.,dissolved in 1 liter of water. Plate Count Agar contains a standard USPformula for nutrient agar, consisting of:

5 g: Pancreatic digest of casein

2.5 g: Yeast extract

1 g: Glucose

15 g: Agar

Four petri dishes were untreated and used as blanks. To the others, induplicate, were added 2.5 ml of 1% acetone solutions of the products ofExamples I, III, IV, and V. All plates were uncovered for 4 hours toexpose them to the spores of adventitious fungi and bacteria, thencovered and stored at 30° C. for 6 days. Ratings were given at thispoint; 0 represents no growth, 5 shows luxuriant colonies of fungi andbacteria. Results were as follows:

    ______________________________________    Product of    Example No.    Growth    ______________________________________    Control        5,5    Example I      0,0    Example III    0,0    Example IV     0,0    Example V      3,0    ______________________________________

EXAMPLE VIII

The compounds of Examples III, IV and V were tested in the vial test ascosurfactants for enhanced oil recovery, using 5% petroleum sulfonate assurfactant in brine (NaCl), adding the cosurfactant to surfactant andnoting the stability of the mixture, as brine tends to cause thesurfactant to separate (salt) out. The brine-surfactant-cosurfactantmixture is then mixed by shaking with crude petroleum and theinterfacial tension (IFT) observed. Low IFT is indicated by easy mixingof the two phases with no separation. Formation of round oil dropletsthat separate quickly indicates a high, ineffective IFT.

The vial test consisted of adding 0.1 g of cosurfactant to 20 ml ofstock solution (5 wt% of crude oil sulfonate, A-152 or V-60 sulfonate,in 0.1N aqueous sodium chloride), adding 2 ml of crude oil, and shakingvial vigorously. A good vial test (+) results in an emulsion stable for2 hours at 25° C.

Products of Examples III and IV proved effective in lowering the IFT inthe vial test, giving mixtures of brine-surfactant-cosurfactant fluidswhich were stable, did not separate, and easily formed mixtures of thefluid with crude petroleum. Product of Example V was ineffective. Thesenovel compounds can be used in solutions at 0.01 to 10% by weight.

EXAMPLE IX

A micellar slug for micellar flooding consisting of 3 (vol)% petroleumsulfonate as surfactant, 2 (vol)% petroleum hydrocarbon, 1 (vol)%cosurfactant comprising a quaternary ammonium compound containinganhydride groups prepared from methyl bromomethylmaleic anhydride andtri-n-hexylamine in a 1.0N NaCl brine solution is prepared. The micellarslug fluid is fed into the high pressure injection pump and is injectedinto a 25 foot section sandstone formation in Crawford County, Ill.,USA, through an injection well at 900 psig. The amount of slug injectedis about 7% of reservoir pore volume and the petroleum hydrocarbon islease crude oil. Pattern of injection is two rows of injection wells andthree rows of producer wells. There are nine wells in each row and totalarea enclosed is 40 acres. Injection and production wells are 460 feetapart and adjacent wells are 115 feet apart. Crude oil productionincreases to recover about 30% of the oil in place at start of theinjection.

What is claimed is:
 1. A composition of the structural formula: ##STR6##wherein X is halogen.
 2. The composition of claim 1 wherein saidcomposition is methyl bromomethylmaleic anhydride.
 3. A method ofpreparing methyl bromomethylmaleic anhydride of the structural formula##STR7## wherein said anhydride is prepared by reacting dimethylmaleicanhydride with bromotrichloromethane in the presence of actinicradiation, and recovering said anhydride by distilling at a temperatureof from about 100° to about 106° C. and from about 0.2 to about 0.3 mmHg.